Zhao Weishan, Li Ming, Xiong Fan, Zhang Dong, Wu Shangong, Zou Hong, Li Wenxiang, Wang Guitang
Key Laboratory of Aquaculture Disease Control, Ministry of Agriculture, and State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
J Eukaryot Microbiol. 2020 Jul;67(4):417-426. doi: 10.1111/jeu.12791. Epub 2020 Mar 1.
The ciliate Balantidium ctenopharyngodoni is the most prominent protist in the guts of grass carp, where it mainly inhabits the creamy luminal contents of the hindgut. Ciliates are generally colonized by microorganisms via phagotrophic feeding. In order to study the intracellular bacteria in this ciliate, we have successfully established it in in vitro culture. Herein, we investigated and compared the bacterial community structures of cultured and freshly collected B. ctenopharyngodoni. The results showed that these two groups exhibited different bacterial communities. The most abundant bacterial family in freshly collected samples was Enterobacteriaceae, while in cultured samples it was Fusobacteriaceae. In addition, a key intracellular bacterium, Cetobacterium somerae, was identified in the cytoplasm of cultured ciliates using fluorescence in situ hybridization (FISH). This study shows that ciliates can retain the intracellular bacteria acquired in the natural habitat for quite a long time, but the bacterial community structure of ciliates eventually changes after a long period of cultivation.
鲤斜管虫是草鱼肠道中最显著的原生生物，它主要栖息在后肠的乳状肠腔内容物中。纤毛虫通常通过吞噬营养摄食而被微生物定殖。为了研究这种纤毛虫中的细胞内细菌，我们已成功在体外培养中建立了该纤毛虫的培养体系。在此，我们研究并比较了培养的和新鲜采集的鲤斜管虫的细菌群落结构。结果表明，这两组呈现出不同的细菌群落。新鲜采集样本中最丰富的细菌科是肠杆菌科，而在培养样本中是梭杆菌科。此外，使用荧光原位杂交（FISH）在培养的纤毛虫细胞质中鉴定出一种关键的细胞内细菌——索氏鲸杆菌。这项研究表明，纤毛虫能够在相当长的时间内保留在自然栖息地中获得的细胞内细菌，但经过长时间培养后，纤毛虫的细菌群落结构最终会发生变化。
